Exhaust-gas turbocharger

Abstract

An exhaust-gas turbocharger ( 1 ), having a shaft ( 2 ) which has an outer diameter (A 2 ); a turbine wheel ( 5 ) which is fastened to the shaft ( 2 ); and a connecting device ( 8 ) via which the shaft ( 2 ) is fastened to the turbine wheel ( 5 ). The shaft ( 2 ) has, in the region of an end side ( 3 ), a shaft shoulder ( 4 ) with an outer diameter (A 4 ) larger than the outer diameter (A 2 ) of the shaft ( 2 ). The turbine wheel ( 5 ) has an external thread portion ( 7 ) integrally formed on its wheel rear side ( 6 ) The connecting device ( 8 ) has a sleeve nut ( 8 A) which is screwed onto the external thread portion ( 7 ) and, in a process, engages behind the shaft shoulder ( 4 ) in order to brace the shaft ( 2 ) against the turbine wheel ( 5 ).

The invention claimed is: 
     
       1. An exhaust-gas turbocharger ( 1 ), having
 a shaft ( 2 ) which has an outer diameter (A 2 ); 
 a turbine wheel ( 5 ) which is fastened to the shaft ( 2 ); and 
 a sleeve nut ( 8 A) by means of which the shaft ( 2 ) is fastened to the turbine wheel ( 5 ); wherein 
 the shaft ( 2 ) has, in the region of an end ( 3 ), a shaft flange ( 4 ) which comprises an outer diameter (A 4 ) larger than the outer diameter (A 2 ) of the shaft ( 2 ), the flange having first axial face facing the turbine wheel and a second axial face facing away from the turbine wheel; 
 the turbine wheel ( 5 ) has a wheel rear side ( 6 ) and has an external thread portion ( 7 ) integrally formed on its wheel rear side ( 6 ); and 
 the sleeve nut ( 8 A) has a first end having an inner diameter at least as large as the flange ( 4 ) outer diameter (A 4 ) and which is internally threaded and which is screwed onto the external thread portion ( 7 ) of the turbine wheel ( 5 ), and a second end having a diameter approximately equivalent to the shaft outer diameter (A 2 ), the second end having an inward flange which engages the shaft flange ( 4 ) second axial face to thereby abut and brace the shaft ( 2 ) flange ( 4 ) first axial face against the turbine wheel ( 5 ). 
 
     
     
       2. The exhaust-gas turbocharger as claimed in  claim 1 , wherein screwing of the sleeve nut ( 8 A) onto the turbine wheel ( 5 ) locks the shaft flange ( 4 ) between the turbine wheel ( 5 ) and the inward flange. 
     
     
       3. The exhaust-gas turbocharger as claimed in  claim 1 , wherein the external thread portion ( 7 ) is arranged on a threaded peg ( 15 ) which is integrally formed on the wheel rear side ( 6 ) of the turbine wheel ( 5 ), wherein the threaded peg ( 15 ) has a coaxial internal bore ( 14 ), and wherein the shaft has a peg dimensioned for mating engagement in the threaded peg ( 15 ) internal bore ( 14 ). 
     
     
       4. The exhaust-gas turbocharger as claimed in  claim 1 , including a positively-locking connection which comprises at least one bore through the sleeve nut ( 8 A) and into the shaft ( 2 ), into which bore a pin is inserted and secured. 
     
     
       5. The exhaust-gas turbocharger as claimed in  claim 1 , including a positively-locking connection which has at least one bore through the sleeve nut ( 8 A) and into the turbine wheel ( 5 ), into which bore a pin is inserted and secured. 
     
     
       6. The exhaust-gas turbocharger as claimed in  claim 1 , including a cohesive connection which has radial or axial bores into the sleeve nut ( 8 A) which, after the bracing of the shaft ( 2 ) and turbine wheel ( 5 ), is welded to the shaft ( 2 ). 
     
     
       7. A rotor ( 12 ) of an exhaust-gas turbocharger ( 1 ), having
 a shaft ( 2 ) which has an outer diameter (A 2 );
 a turbine wheel ( 5 ) which is fastened to the shaft ( 2 ); and 
 
 a sleeve nut ( 8 A) by means of which the shaft ( 2 ) is fastened to the turbine wheel ( 5 ); wherein 
 the shaft ( 2 ) has, in the region of an end ( 3 ), a shaft flange ( 4 ) which comprises an outer diameter (A 4 ) larger than the outer diameter (A 2 ) of the shaft ( 2 ), the flange having first axial face facing the turbine wheel and a second axial face facing away from the turbine wheel; 
 the turbine wheel ( 5 ) has a wheel rear side ( 6 ) and has an external thread portion ( 7 ) integrally formed on its wheel rear side ( 6 ); and 
 the sleeve nut ( 8 A) has a first end having an inner diameter at least as large as the flange ( 4 ) outer diameter (A 4 ) and which is internally threaded and which is screwed onto the external thread portion ( 7 ) of the turbine wheel ( 5 ), and a second end having a diameter approximately equivalent to the shaft outer diameter (A 2 ), the second end having an inward flange which engages the shaft flange ( 4 ) second axial face to thereby abut and brace the shaft ( 2 ) flange ( 4 ) first axial face against the turbine wheel ( 5 ). 
 
     
     
       8. The rotor as claimed in  claim 7 , wherein screwing of the sleeve nut ( 8 A) onto the turbine wheel ( 5 ) locks the shaft flange ( 4 ) between the turbine wheel ( 5 ) and the inward flange. 
     
     
       9. The rotor as claimed in  claim 7 , wherein the external thread portion ( 7 ) is arranged on a threaded peg ( 15 ) which is integrally formed on the wheel rear side ( 6 ) of the turbine wheel ( 5 ), wherein the threaded peg ( 15 ) has a coaxial internal bore ( 14 ), and wherein the shaft has a peg dimensioned for tight engagement in the threaded peg ( 15 ) internal bore ( 14 ). 
     
     
       10. The rotor as claimed in  claim 7 , including a positively-locking connection which comprises at least one bore through the sleeve nut ( 8 A) and into the shaft ( 2 ), into which bore a pin is inserted and secured. 
     
     
       11. The rotor as claimed in  claim 7 , including a positively-locking connection which has at least one bore through the sleeve nut ( 8 A) and into the turbine wheel ( 5 ), into which bore a pin is inserted and secured. 
     
     
       12. The rotor as claimed in  claim 7 , including a cohesive connection which has radial or axial bores into the sleeve nut ( 8 A) which, after the bracing of the shaft ( 2 ) and turbine wheel ( 5 ), is welded to the shaft ( 2 ).